Limited connectivity - no IP found

I am facing this problem twice or thrice in a month. My lan gets disconnected and when i try to reconnect it, it gives message of 'no or limited connectivity', i have tried a lot of stuff (searched from different forums) but no help, the problem gets resolved by itself after a day or two. I dont know what is the issue.. there are 12pc on the lan and only 1 pc (out of 6 that are sharing documents with others) is having the problem.. Pls help!!
I often get my lan disconnected and then reconnected itself also..

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The quickest and easiest two things that you can try on the single machine
having the connectivity issue are:

1) Try re-installing the NIC driver, or look on the mfg's website to see if
there is an updated driver for the NIC

-and-

2) Just try replacing the NIC with a known working one. Perhaps you can pull
the NIC out of one of the machines that ISN'T having the problem, and swap
the two out. If your connectivity issue follows the NIC to whatever machine
it happens to be in, then, voilá! You know it's the card causing the
problems.

Hello,
I have seen this problem before, but please I need some more information.
Is there any wireless boxes (laptops or PDAs) or any Mobile devices that
connect to your LAN? Does your backbone (the isp hardline) feed into a
router? Knowing these things will let me help you better.
Louis

Check the ethernet cable, you may have an intermittent fault on either one of the RJ45 plugs or the cable itself. Is it easy to temporarily run another cable ? If the cable doesn't solve it then try re-seating the NIC in the PC that's affected (for a plug in card) or try a PCI NIC if using the on-board one.

Could it be as easy as a bad network cable? How about another computer with
the same name on the network? My next step would be to put a PCI network
card in to be sure it's not an intermittant hardware problem.

How many devices do you have on your network? How do they get their IP
addresses assigned? Make sure there are enough IP's in the DHCP pool to
cover all the devices. If you are using wireless, make sure it is
secured so your neighbors don't use up your IP's...

This sounds like a router issue.
A basic check;
1. Is the ISP connection at the cable modem available?
2. Is the router searching for the internet or no lites on the router?
3. Is the pc's NIC operating look for the flashing light at the cable connection on the back of the PC.
If all pc's have the same issue at the same time then it is located at the router, modem or the ISP (Internet Service Provider) is causing the outage.
I have found many times the router is over heating and causing a reboot of the router. Keeping the router and modem in a well ventilated space should reduce the chances of this happening.

Louis:
Usually the simplest solution is the one that gets overlooked. I am assuming that your 'problem machine' is connected to the LAN via wireless adapter, and, if so, you are probably using the adapter's software utility to configure and connect to the network. Run 'services.msc' through the 'start' 'run' function in XP, and check the 'Wireless Zero' service. If it is running, stop it, and in the properties window, set it's function to 'disabled'.
Reboot the machine and see if that cures your problem. The wireless zero service does not play well with adapter utility software, and turning it off usually solves connectivity problems.
Duke Jones

the cabels are fine! i have updated the drivers also, still no luck..
the problem is with the NIC card, i guess i have to change it.. I reseated it in another PC but it was working fine and whn i again put it bck in the infected PC it was working fine.. As i told you before it gets resolved itself so its hard to check it.
I guess i should exchange this NIC with a new one..
@ lee.. power settings is not the issue
@ mike.. Yes i have enough IPs and all the devices have their IPs assigned automatically
@billjames.. only my Pc is having the problem, all other PCs are working just fine..
@ duke.. no its a wired network

Toolbox windows-xp-pro-lI would replace the cable anyway. I have had cables check okay and still not work. Recently I had a machine that worked fine on the network/internet until you tried to open a large file, then it would not work. After a day I swapped cables out, no more problems.
Dan

OK, that is great information. Believe this or not, but check your cables,
ESP the ones that leads from your computer to your switch. Or if you ran a
line right to the router. One bad cable could cause this problem. Please
try this first.
Louis

You gotta try the basics first. Swap the card out with another one and
choose a different PCI slot if possible.
If you're determined to see if it's a hardware issue set the NIC to
half-duplex. I've seen cards that have gone bad work intermittantly
at full-duplex.
Also, resetting the WINSOCK can solve all types of problems, although I've
never seen corrupt WINSOCK fix itself.
Opena command prompt and type ping loopback. See if it shows that it's
pinging 127.0.0.1 or do you get corrupt letters for the IP? Either way type
"netsh winsock reset catalog" without the quotes and hit enter. Reboot the
machine and see what happens.

The problem is resolved, i did nothing.. turn off the computer as i do everyday and the next day (i.e today) its working fine... i have not figured out yet what the reason was..
@ Patel.. Firewall is on, yes I am on the same workgroup,and i am using Windows XP pro SP3
@ Dan.. i restarted the router many times (before your post), but no luck..
@ loutho.. I changed the cabels, infact i connected the PC directly with the switch with a cabel that was working fine (took it out from another PC) but didn't work..
@ James.. I will try your solution as soon as i will get the problem bck again, because this occurs twice or thrice a month and gets resolved itself..
@ Vikash.. I am thinking of changing the LAN card, but just waiting for the next time I get the problem, because I am getting curious about the issue :)

Hey,
I am glad you resolved it. Thank you for trying the cable, my reason for
asking you to do this is that 568a and 568b cables most of time run fine in
the same network, but I have found that the 568a will drop packets or
worse.(older technogy, gigabit network speeds.) Also, you said that didn't
have wireless; if you did I wanted to see if your access point was locked
down. People other than your network users could cause some of your
issues. But now that you are good, then that's great. Good luck.
Louis

Intermittent faults are the worst to track down and if it happens again you've done most of the troubleshooting already so next step would be to replace the NIC. After that you are looking at software and perhaps a flaky TCP/IP stack. As ever with fault finding, one step at a time until you crack it.

You could test your TCP/IP stack by pinging your loopback IP which will be 127.0.0.1
To test the NIC is working Ping your IP address so whatever IP your router has assigned you eg. 192.168.1.100 or something like that you can find your IP by typing IPCONFIG /all in the CMD window.
To test the LAN ping your gateway eg 192.168.1.1
To test the internet ping an external address like google.comRegards Lee

@ Amr Darweesh.. if its a torjan horse than why is it happening only on my PC? no other PC on the network has this issue..can u explain this a little bit to me?
@ dark.an9el.. Yup! I hv tried that already
@ Louis and Barry.. Thank you for your concern..
@ nishant.. I tried this before.. but this time something else happend also..
Well i started from scratch, installed windows updates cleaned my PC, reinstalled the drivers (updated ones) but then i got another weird error. I was connected to the LAN (with a new IP address) but my status was 'Acquiring network address', i tried to use static ip address, but nothing happened. The problem again got resolved itself, after 4 days (working fine with both dynamic and static ip addresses).. but this is really frustrating that i am continously getting weird kind of problems..

I would check to see if the RJ45 cable in the back is snug ..... If wireless ensure you are getting a clean signal all the time. I think that windows has a maximum amount of concurrent network connections allowable without disconnecting. This would be some type of virus (using you as a beacon or "sender") You can see this information when you are connected by issuing the command netstat -an at the command prompt. If you see alot of foreign connections (alot --> like 50) then you have something wrong. Otherwise I dunno ....except maybe incompatible encryption or bad handshakes due to line loss (bad cable or shorted) When installing Windows initially you want to get the updates as quickly as possible cuz there are viruses out there scanning for vulnerabilities not yet patched.Good day,Conrad

I have the same problem with my customer's PC. All seems to be O.K. but after couple of minutes is traffic on port 80 (ONLY !) blocked. Traffic on other ports is normal. It means I cannot connect to HTTP, but POP3, SMTP, HTTPS are functional. I tried to find malware via SpyBot, AdAware, Malwarebyte's AntiMalware but without any positive effect. One more note - this behaviour doesn't occur when I work in Safe Mode with network. It means that it has to be software problem. (Sorry for my English ...)

Toolbox windows-xp-pro-lThat sounds like there must be a firewall configured on your network. HTTPS protocol, port 443 means it only allows secure http traffic to flow. Unlikely that it is that particular without good reasoning behind it. If you aren't the Network/LAN administrator, then you need to talk to your IT staff, find out if or why it was configured that. The listed protocols, POP3 = 110, SMTP = 25, HTTP=80 and HTTPS=443 indicate that only mail/exchange and web protocols are permitted. Personally, I see that as the mark of a security conscious administrator - a bit tight, but a also a good plan, if it was done intentionally.

I hope this question has been asked and confirmed?
you mention that you have 12 PC (nodes) on this LAN. If this a workgroup (as opposed to a Domain, with server running server OS). The official node limit for XP workgroup is 10 concurrent connection. You are over that limit, especially if you have network printer or other devices that use IP address.
Once that limit is reached it will not allocate any new IP addresses. Lifetime for the IP addresses are configurable and will timeout, be available for re-assignment.
If this issue is still unresolved, check your IP address assigned count.